Multi-carrier operation for wireless systems

ABSTRACT

The present disclosure generally relates to an uplink control signal design for wireless system. One example method of a subscriber station (SS) includes performing network entry in a multi-carrier wireless environment using a primary carrier, receiving timing information corresponding to the primary carrier, receiving a first control signaling via the primary carrier, the first control signaling assigning at least one secondary carrier, transmitting uplink data via the secondary carrier using an uplink transmission timing of the secondary carrier, the uplink transmission timing of the secondary carrier being assigned the same as an uplink transmission timing of the primary carrier, and determining an adjustment of the uplink transmission timing or frequency of the secondary carrier.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of the non-provisional applicationSer. No. 15/596,166 filed on May 16, 2017, which is a continuation ofthe non-provisional application Ser. No. 14/731,059 filed on Jun. 4,2015, which is a continuation of the non-provisional application Ser.No. 14/263,623 filed on Apr. 28, 2014, which is a continuation of thenon-provisional application Ser. No. 12/874,853, which is acontinuation-in-part of the non-provisional application Ser. No.12/806,193 resulting from conversion under 37 C.F.R. § 1.53(c)(3) ofU.S. provisional patent application Ser. No. 61/239,204 filed on Sep. 2,2009, which claims the benefit of U.S. provisional patent applicationSer. No. 61/094,644 filed on Sep. 5, 2008.

This application claims the benefit of U.S. provisional patentapplication Ser. No. 61/239,204 filed on Sep. 2, 2009, which is herebyincorporated by reference in its, entirety.

The subject matter of the present invention is related to U.S. PatentApplication Ser. No. 61/035,363, filed on Mar. 10, 2008, herebyincorporated by reference herein.

The subject matter of the present invention is also related to U.S.patent application Ser. No. 10/141,013, filed on May 8, 2002 (now U.S.Pat. No. 7,492,737), hereby incorporated by reference herein.

FIELD

The application relates to wireless communication techniques in general,and more specifically to multi-carrier operations for wireless systems.

BACKGROUND

The demand for services in which data is delivered via a wirelessconnection has grown in recent years and is expected to continue togrow. Included are applications in which data is delivered via cellularmobile telephony or other mobile telephony, personal communicationssystems (PCS) and digital or high definition television (HDTV). Thoughthe demand for these services is growing, the channel bandwidth overwhich the data may be delivered is limited. Therefore, it is desirableto deliver data at high speeds over this limited bandwidth in anefficient, as well as cost effective, manner.

One possible approach for delivering high speed data over a channel isby using Orthogonal Frequency Division Multiplexing (OFDM). Thehigh-speed data signals are divided into tens or hundreds of lower speedsignals that are transmitted in parallel over respective frequencieswithin a radio frequency (RF) signal that are known as sub-carrierfrequencies (“sub-carriers”). The frequency spectra of the sub-carriersoverlap so that the spacing between them is minimized. The sub-carriersare also orthogonal to each other so that they are statisticallyindependent and do not create crosstalk or otherwise interfere with eachother. As a result, the channel bandwidth is used much more efficientlythan in conventional single carrier transmission schemes such as AM/FM(amplitude or frequency modulation).

Another approach to providing more efficient use of the channelbandwidth is to transmit the data using a base station having multipleantennas and then receive the transmitted data using a remote stationhaving multiple receiving antennas, referred to as MultipleInput-Multiple Output (MIMO). The data may be transmitted such thatthere is spatial diversity between the signals transmitted by therespective antennas, thereby increasing the data capacity by increasingthe number of antennas. Alternatively, the data is transmitted such thatthere is temporal diversity between the signals transmitted by therespective antennas, thereby reducing signal fading.

The notion of using multiple carriers in a wireless system is a knownconcept. Multiple carriers offer the possibility of providing the enduser with a rich portfolio of services, such as voice and high speeddata applications. However, there is a need in the industry to developspecific operational techniques and methodologies for such wirelesssystems in order to improve network performance and efficiency.

SUMMARY

As embodied and broadly described herein the invention also provides amethod for an SS to perform network entry in a multi-carrier wirelessenvironment that has a plurality of primary carriers and at least onesecondary carrier associated with a BS. The method comprising receivingat the SS control information sent over one of the primary carriers,processing with the SS the control information to determine if thenetwork entry is to be performed over the one of the primary carriers ora different primary carrier of the plurality of primary carriers andperforming the network entry on the basis of the determining.

As embodied and broadly described herein the invention also provides amethod, in a multi-carrier wireless environment that has a primarycarrier and at least one secondary carrier associated with a BS, whichcomprises, the BS sending over the primary carrier control informationto an SS and the SS initiating in response to the control information aUL ranging with the secondary carrier.

As embodied and broadly described herein the invention also provides, ina multi-carrier wireless environment that has a primary carrier and atleast one secondary carrier associated with a BS, a method fordelivering system information on the secondary carrier to an SS, whichcomprises, the BS sending over the primary carrier control data to anSS, the control data conveying decoding information and the SS decodinga broadcast channel of the secondary carrier on the basis of thedecoding information.

As embodied and broadly described herein the invention provides, in amulti-carrier wireless environment that has a plurality of primarycarriers and at least one secondary carrier associated with a BS, amethod for performing intra-BS handover, which includes the BS sendingto the SS over a first of the plurality of the primary carriers controldata and the SS switching to a second of the plurality of the primarycarriers in response to the control data.

As embodied and broadly described herein the invention also provides amethod for performing handover of an SS from a first BS to a second BS,wherein the first BS manages a first multicarrier wireless environmenthaving at least one primary carrier and a secondary carrier; and thesecond BS manages a second multicarrier wireless environment having atleast one primary carrier and a secondary carrier. The method including,the first BS sending to the SS over the primary carrier in the firstenvironment control data, the control data conveying a multi carrierconfiguration information of the second wireless environment and the SSswitching to the second BS for services on the basis of the controldata.

As embodied and broadly described herein, the invention further providesa method for managing sleep mode of an SS in a multicarrier wirelessenvironment that is served by a BS and has a primary carrier and asecondary carrier. The method includes, the SS monitoring successivelistening windows on the primary carrier for data traffic indication, adata traffic is indication in any one of the listening windows beingindicative of data traffic for the SS and whether the data traffic willbe delivered over the primary carrier or the secondary carrier. The SSthen monitors the carrier indicated by the data traffic indication forthe data traffic.

As embodied and broadly described herein the invention also provides amethod for feeding back to a BS CQI in a wireless multi-carrierenvironment serviced by the BS, wherein the multi-carrier environmenthas a primary carrier and a secondary carrier. The method includesestablishing communication between an SS and the BS over the primarycarrier and the secondary carrier, wherein the primary carrierestablishes a UL feedback control channel. The method further includesgenerating at the SS CQI in connection with the secondary carrier andtransmitting the CQI to the BS over the UL feedback control channel.

As embodied and broadly described herein, the invention further includesa method for feeding back to a BS CQI in a wireless multi-carrierenvironment serviced by the BS, wherein the multi-carrier environmenthas a primary carrier and a secondary carrier. The method includesestablishing communication between an SS and the BS over the primarycarrier and the secondary carrier, wherein the secondary carrierestablishes a UL feedback control channel. The method further includesgenerating at the SS CQI in connection with the secondary carrier andtransmitting the CQI to the BS over the UL feedback control channel.

Aspects and features of the present application will become apparent tothose ordinarily skilled in the art upon review of the followingdescription of specific embodiments of a disclosure in conjunction withthe accompanying drawing figures and appendices.

DESCRIPTION OF THE DRAWINGS

Embodiments of the present application will now be described, by way ofexample only, with reference to the accompanying drawing figures,wherein:

FIG. 1 is a block diagram of a cellular communication system;

FIG. 2 is a block diagram of an example base station that might be usedto implement some embodiments of the present 5 application;

FIG. 3 is a block diagram of an example wireless terminal that might beused to implement some embodiments of the present application;

FIG. 4 is a block diagram of an example relay station that might be usedto implement some embodiments of the present application;

FIG. 5 is a block diagram of a logical breakdown of an example OFDMtransmitter architecture that might be used to implement someembodiments of the present application;

FIG. 6 is a block diagram of a logical breakdown of an example OFDMreceiver architecture that might be used to implement some embodimentsof the present application;

FIG. 7 is FIG. 1 of IEEE 802.16m-08/003r1, an Example of overall networkarchitecture;

FIG. 8 is FIG. 2 of IEEE 802.16m-08/003r1, a Relay Station in overallnetwork architecture;

FIG. 9 is FIG. 3 of IEEE 802.16m-08/003r1, a System Reference Model;

FIG. 10 is FIG. 4 of IEEE 802.16m-08/003r1, The IEEE 802.16m ProtocolStructure;

FIG. 11 is FIG. 5 of IEEE 802.16m-08/003r1, The IEEE 802.16m MS/BS DataPlane Processing Flow;

FIG. 12 is FIG. 6 of IEEE 802.16m-08/003r1, The IEEE 802.16m MS/BSControl Plane Processing Flow;

FIG. 13 is FIG. 7 of IEEE 802.16m-08/003r1, Generic protocolarchitecture to support multicarrier system;

FIG. 14 is a high level block diagram of a process for distinguishingbetween primary and secondary carriers when an SS is performing networkentry operation;

FIG. 15 is a more detailed block diagram illustrating steps forperforming a network entry operation in a wireless multi carrier system;

FIG. 16 is a block diagram illustrating a method for obtaining systeminformation on secondary carriers in a wireless multi carrier operation;

FIG. 17 is a block diagram of a process for performing handover in awireless multi carrier system;

FIG. 18 is a block diagram of a process for performing sleep modemanagement in a wireless multi carrier system;

FIG. 19 is a block diagram of a process for providing to a BS feedbackon channel quality, according to a first example of implementation ofthe invention;

FIG. 20 is a block diagram of a process for providing to a BS feedbackon channel quality, according to a second example of implementation ofthe invention;

FIG. 21 is a block diagram of a process for providing to a BS feedbackon channel quality, according to a third example of implementation ofthe to invention;

FIGS. 22(a)- 22(d) are examples of different carrier assignment.

FIG. 23 is an example protocol structure for high speed multi-carrierwireless network.

FIG. 24 is an example resource management interface between Layer2/3 andPhysical Layer

FIG. 25 is a diagram of example MAC states.

FIG. 26 is a diagram of example forward CDMA channels in the PrimaryCarrier.

FIGS. 27-28 are diagrams of example frame configurations of BroadcastPointer Channel (BPCH).

Like reference numerals are used in different figures to denote similarelements.

DETAILED DESCRIPTION

Referring to the drawings, FIG. 1 shows a base station controller (BSC)10 which controls wireless communications within multiple cells 12,which cells are served by corresponding base stations (BS) 14. In someconfigurations, each cell is further divided into multiple sectors 13 orzones (not shown). In general, each BS 14 facilitates communicationsusing OFDM with subscriber stations (SS) 16 which can be any entitycapable of communicating with the base station, and may include mobileand/or wireless terminals or fixed terminals, which are within the cell12 associated with the corresponding BS 14. If SSs 16 moves in relationto the BSs 14, this movement results in significant fluctuation inchannel conditions. As illustrated, the BSs 14 and SSs 16 may includemultiple antennas to provide spatial diversity for communications. Insome configurations, relay stations 15 may assist in communicationsbetween BSs 14 and wireless terminals 16. SS 16 can be handed off 18from any cell 12, sector 13, zone (not shown), BS 14 or relay 15 toanother cell 12, sector 13, zone (not shown), BS 14 or relay 15. In someconfigurations, BSs 14 communicate with each and with another network(such as a core network or the internet, both not shown) over a backhaulnetwork 11. In some configurations, a base station controller 10 is notneeded.

With reference to FIG. 2, an example of a BS 14 is illustrated. The BS14 generally includes a control system 20, a baseband processor 22,transmit circuitry 24, receive circuitry 26, multiple antennas 28, and anetwork interface 30. The receive circuitry 26 receives radio frequencysignals bearing information from one or more remote transmittersprovided by SSs 16 (illustrated in FIG. 3) and relay stations 15(illustrated in FIG. 4). A low noise amplifier and a filter (not shown)may cooperate to amplify and remove broadband interference from thesignal for processing. Downconversion and digitization circuitry (notshown) will then downconvert the filtered, received signal to anintermediate or baseband frequency signal, which is then digitized intoone or more digital streams.

The baseband processor 22 processes the digitized received signal toextract the information or data bits conveyed in the received signal.This processing typically comprises demodulation, decoding, and errorcorrection operations. As such, the baseband processor 22 is generallyimplemented in one or more digital signal processors (DSPs) orapplication-specific integrated circuits (ASICs). The receivedinformation is then sent across a wireless network via the networkinterface 30 or transmitted to another SS 16 serviced by the BS 14,either directly or with the assistance of a relay 15.

On the transmit side, the baseband processor 22 receives digitized data,which may represent voice, data, or control information, from thenetwork interface 30 under the control of control system 20, and encodesthe data for transmission. The encoded data is output to the transmitcircuitry 24, where it is modulated by one or more carrier signalshaving a desired transmit frequency or frequencies. A power amplifier(not shown) will amplify the modulated carrier signals to a levelappropriate for transmission, and deliver the modulated carrier signalsto the antennas 28 through a matching network (not shown). Modulationand processing details are described in greater detail below.

With reference to FIG. 3, an example of a subscriber station (SS) 16 isillustrated. SS 16 can be, for example a mobile station. Similarly tothe BS 14, the SS 16 will include a control system 32, a basebandprocessor 34, transmit circuitry 36, receive circuitry 38, multipleantennas 40, and user interface circuitry 42. The receive circuitry 38receives radio frequency signals bearing information from one or moreBSs 14 and relays 15. A low noise amplifier and a filter (not shown) maycooperate to amplify and remove broadband interference from the signalfor processing. Downconversion and digitization circuitry (not shown)will then downconvert the filtered, received signal to an intermediateor baseband frequency signal, which is then digitized into one or moredigital streams.

The baseband processor 34 processes the digitized received signal toextract is the information or data bits conveyed in the received signal.This processing typically comprises demodulation, decoding, and errorcorrection operations. The baseband processor 34 is generallyimplemented in one or more digital signal processors (DSPs) andapplication specific integrated circuits (ASICs). For transmission, thebaseband processor 34 receives digitized data, which may representvoice, video, data, or control information, from the control system 32,which it encodes for transmission. The encoded data is output to thetransmit circuitry 36, where it is used by a modulator to modulate oneor more carrier signals that is at a desired transmit frequency orfrequencies. A power amplifier (not shown) will amplify the modulatedcarrier signals to a level appropriate for transmission, and deliver themodulated carrier signal to the antennas 40 through a matching network(not shown). Various modulation and processing techniques available tothose skilled in the art are used for signal transmission between the SSand the base station, either directly or via the relay station.

In OFDM modulation, the transmission band is divided into multiple,orthogonal subcarriers. Each subcarrier is modulated according to thedigital data to be transmitted. Because OFDM divides the transmissionband into multiple subcarriers, the bandwidth per carrier decreases andthe modulation time per carrier increases. Since the multiplesubcarriers are transmitted in parallel, the transmission rate for thedigital data, or symbols (discussed later), on any given subcarrier islower than when a single carrier is used.

OFDM modulation utilizes the performance of an Inverse Fast FourierTransform (IFFT) on the information to be transmitted. For demodulation,the performance of a Fast Fourier Transform (FFT) on the received signalrecovers the transmitted information. In practice, the IFFT and FFT areprovided by digital signal processing carrying out an Inverse DiscreteFourier Transform (IDFT) and Discrete Fourier Transform (DFT),respectively. Accordingly, the characterizing feature of OFDM modulationis that orthogonal subcarriers are generated for multiple bands within atransmission channel. The modulated signals are digital signals having arelatively low transmission rate and capable of staying within theirrespective bands. The individual subcarriers are not modulated directlyby the digital signals. Instead, all subcarriers are modulated at onceby IFFT processing.

In operation, OFDM is preferably used for at least the downlinktransmission from the BSs 14 to the SSs 16. Each BS 14 is equipped with“n” transmit antennas 28 (n>=1), and each SS 16 is equipped with “m”receive antennas 40 (m>=1). Notably, the respective antennas can be usedfor reception and transmission using appropriate duplexers or switchesand are so labeled only for clarity.

When relay stations 15 are used, OFDM is preferably used for downlinktransmission from the BSs 14 to the relays 15 and from relay stations 15to the SSs 16.

With reference to FIG. 4, an example of a relay station 15 isillustrated. Similarly to the BS 14, and the SS 16, the relay station 15will include a control system 132, a baseband processor 134, transmitcircuitry 136, receive circuitry 138, multiple antennas 130, and relaycircuitry 142. The relay circuitry 142 enables the relay 14 to assist incommunications between a base station 16 and SSs 16. The receivecircuitry 138 receives radio frequency signals bearing information fromone or more BSs 14 and SSs 16. A low noise amplifier and a filter (notshown) may cooperate to amplify and remove broadband interference fromthe signal for processing. Downconversion and digitization circuitry(not shown) will then downconvert the filtered, received signal to anintermediate or baseband frequency signal, which is then digitized intoone or more digital streams.

The baseband processor 134 processes the digitized received signal toextract the information or data bits conveyed in the received signal.This processing typically comprises demodulation, decoding, and errorcorrection operations. The baseband processor 134 is generallyimplemented in one or more digital signal processors (DSPs) andapplication specific integrated circuits (ASICs).

For transmission, the baseband processor 134 receives digitized data,which may represent voice, video, data, or control information, from thecontrol system 132, which it encodes for transmission. The encoded datais output to the transmit circuitry 136, where it is used by a modulatorto modulate one or more carrier signals that is at a desired transmitfrequency or frequencies. A power amplifier (not shown) will amplify themodulated carrier signals to a level appropriate for transmission, anddeliver the modulated carrier signal to the antennas 130 through amatching network (not shown). Various modulation and processingtechniques available to those skilled in the art are used for signaltransmission between the SS and the base station, either directly orindirectly via a relay station, as described above.

With reference to FIG. 5, a logical OFDM transmission architecture willbe described. Initially, the base station controller 10 will send datato be transmitted to various SSs 16 to the BS 14, either directly orwith the assistance of a relay station 15. The BS 14 may use theinformation on the quality of channel associated with the SSs toschedule the data for transmission as well as select appropriate codingand modulation for transmitting the scheduled data. The quality of thechannel is found using control signals, as described in more detailsbelow. Generally speaking, however, the quality of channel for each SS16 is a function of the degree to which the channel amplitude (orresponse) varies across the OFDM frequency band.

Scheduled data 44, which is a stream of bits, is scrambled in a mannerreducing the peak-to-average power ratio associated with the data usingdata scrambling logic 46. A cyclic redundancy check (CRC) for thescrambled data may be determined and appended to the scrambled datausing CRC adding logic 48. Next, channel coding is performed usingchannel encoder logic 50 to effectively add redundancy to the data tofacilitate recovery and error correction at the SS 16. Again, thechannel coding for a particular SS 16 may be based on the quality ofchannel. In some implementations, the channel encoder logic 50 usesknown Turbo encoding techniques. The encoded data is then processed byrate matching logic 52 to compensate for the data expansion associatedwith encoding.

Bit interleaver logic 54 systematically reorders the bits in the encodeddata to minimize the loss of consecutive data bits. The resultant databits are systematically mapped into corresponding symbols depending onthe modulation scheme chosen by mapping logic 56. The modulation schememay be, for example, Quadrature Amplitude Modulation (QAM), QuadraturePhase Shift Key (QPSK) or Differential Phase Shift Keying (DPSK)modulation. For transmission data, the degree of modulation may bechosen based on the quality of channel for the particular SS. Thesymbols may be systematically reordered to further bolster the immunityof the transmitted signal to periodic data loss caused by frequencyselective fading using symbol interleaver logic 58.

At this point, groups of bits have been mapped into symbols representinglocations in an amplitude and phase constellation. When spatialdiversity is desired, blocks of symbols are then processed by space-timeblock code (STC) encoder logic 60, which modifies the symbols in afashion making the transmitted signals more resistant to interferenceand more readily decoded at a SS 16. The STC encoder logic 60 willprocess the incoming symbols and provide “n” outputs corresponding tothe number of transmit antennas 28 for the BS 14. The control system 20and/or baseband processor 22 as described above with respect to FIG. 5will provide a mapping control signal to control STC encoding. At thispoint, assume the symbols for the “n” outputs are representative of thedata to be transmitted and capable of being recovered by the SS 16.

For the present example, assume the BS 14 has two antennas 28 (n=2) andthe STC encoder logic 60 provides two output streams of symbols.Accordingly, each of the symbol streams output by the STC encoder logic60 is sent to a corresponding IFFT processor 62, illustrated separatelyfor ease of understanding. Those skilled in the art will recognize thatone or more processors may be used to provide such digital signalprocessing, alone or in combination with other processing describedherein. The IFFT processors 62 will preferably operate on the respectivesymbols to provide an inverse Fourier Transform. The output of the IFFTprocessors 62 provides symbols in the time domain. The time domainsymbols are grouped into frames, which are associated with a prefix byprefix insertion logic 64. Each of the resultant signals is up-convertedin the digital domain to an intermediate frequency and converted to ananalog signal via the corresponding digital up-conversion (DUC) anddigital-to-analog (D/A) conversion circuitry 66. The resultant (analog)signals are then simultaneously modulated at the desired RF frequency,amplified, and transmitted via the RF circuitry 68 and antennas 28.Notably, pilot signals known by the intended SS 16 are scattered amongthe sub-carriers. The SS 16 may use the pilot signals for channelestimation.

Reference is now made to FIG. 6 to illustrate reception of thetransmitted signals by a SS 16, either directly from BS 14 or with theassistance of relay 15. Upon arrival of the transmitted signals at eachof the antennas 40 of the SS 16, the respective signals are demodulatedand amplified by corresponding RF circuitry 70. For the sake ofconciseness and clarity, only one of the two receive paths is describedand illustrated in detail. Analog-to-digital (ND) converter anddown-conversion circuitry 72 digitizes and downconverts the analogsignal for digital processing. The resultant digitized signal may beused by automatic gain control circuitry (AGC) 74 to control the gain ofthe amplifiers in the RF circuitry 70 based on the received signallevel. Initially, the digitized signal is provided to synchronizationlogic 76, which includes coarse synchronization logic 78, which buffersseveral OFDM symbols and calculates an auto-correlation between the twosuccessive OFDM symbols. A resultant time index corresponding to themaximum of the correlation result determines a fine synchronizationsearch window, which is used by fine synchronization logic 80 todetermine a precise framing starting position based on the headers. Theoutput of the fine synchronization logic 80 facilitates frameacquisition by frame alignment logic 84. Proper framing alignment isimportant so that subsequent FFT processing provides an accurateconversion from the time domain to the frequency domain. The finesynchronization algorithm is based on the correlation between thereceived pilot signals carried by the headers and a local copy of theknown pilot data. Once frame alignment acquisition occurs, the prefix ofthe OFDM symbol is removed with prefix removal logic 86 and resultantsamples are sent to frequency offset correction logic 88, whichcompensates for the system frequency offset caused by the unmatchedlocal oscillators in the transmitter and the receiver. Preferably, thesynchronization logic 76 includes frequency offset and clock estimationlogic 82, which is based on the headers to help estimate such effects onthe transmitted signal and provide those estimations to the correctionlogic 88 to properly process OFDM symbols.

At this point, the OFDM symbols in the time domain are ready forconversion to the frequency domain using FFT processing logic 90. Theresults are frequency domain symbols, which are sent to processing logic92. The processing logic 92 extracts the scattered pilot signal usingscattered pilot extraction logic 94, determines a channel estimate basedon the extracted pilot signal using channel estimation logic 96, andprovides channel responses for all sub-carriers using channelreconstruction logic 98. In order to determine a channel response foreach of the sub-carriers, the pilot signal is essentially multiple pilotsymbols that are scattered among the data symbols throughout the OFDMsub-carriers in a known pattern in both time and frequency. Continuingwith FIG. 6, the processing logic compares the received pilot symbolswith the pilot symbols that are expected in certain sub-carriers atcertain times to determine a channel response for the sub-carriers inwhich pilot symbols were transmitted. The results are interpolated toestimate a channel response for most, if not all, of the remainingsub-carriers for which pilot symbols were not provided. The actual andinterpolated channel responses are used to estimate an overall channelresponse, which includes the channel responses for most, if not all, ofthe sub-carriers in the OFDM channel.

The frequency domain symbols and channel reconstruction information,which are derived from the channel responses for each receive path areprovided to an STC decoder 100, which provides STC decoding on bothreceived paths to recover the transmitted symbols. The channelreconstruction information provides equalization information to the STCdecoder 100 sufficient to remove the effects of the transmission channelwhen processing the respective frequency domain symbols.

The recovered symbols are placed back in order using symbolde-interleaver logic 102, which corresponds to the symbol interleaverlogic 58 of the transmitter. The de-interleaved symbols are thendemodulated or de-mapped to a corresponding bit stream using de-mappinglogic 104. The bits are then de-interleaved using bit de-interleaverlogic 106, which corresponds to the bit interleaver logic 54 of thetransmitter architecture. The de-interleaved bits are then processed byrate de-matching logic 108 and presented to channel decoder logic 110 torecover the initially scrambled data and the CRC checksum. Accordingly,CRC logic 112 removes the CRC checksum, checks the scrambled data intraditional fashion, and provides it to the de-scrambling logic 114 fordescrambling using the known base station de-scrambling code to recoverthe originally transmitted data 116.

In parallel to recovering the data 116, a CQI signal comprising anindication of channel quality, or at least information sufficient toderive some knowledge of channel quality at the BS 14, is determined andtransmitted to the BS 14. transmission of the CQI signal will bedescribed in more detail below. As noted above, the CQI may be afunction of the carrier-to-interference ratio (CR), as well as thedegree to which the channel response varies across the varioussub-carriers in the OFDM frequency band. For example, the channel gainfor each sub-carrier in the OFDM frequency band being used to transmitinformation may be compared relative to one another to determine thedegree to which the channel gain varies across the OFDM frequency band.Although numerous techniques are available to measure the degree ofvariation, one technique is to calculate the standard deviation of thechannel gain for each sub-carrier throughout the OFDM frequency bandbeing used to transmit data. In some embodiments, a relay station mayoperate in a time division manner using only one radio, or alternativelyinclude multiple radios.

FIGS. 1 to 6 provide one specific example of a communication system thatcould be used to implement embodiments of the application. It is to beunderstood that embodiments of the application can be implemented withcommunications systems having architectures that are different than thespecific example, but that operate in a manner consistent with theimplementation of the embodiments as described herein.

FIGS. 7-13 of the present application correspond to FIGS. 1-7 of IEEE802.16m-08/003r1.

The description of these figures in of IEEE 802.16m-08/003r1 isincorporated herein by reference.

Turning now to FIG. 7, there is shown an example network referencemodel, which is a logical representation of a network that supportswireless communications among the aforementioned BSs 14, SSs 16 andrelay stations (RSs) 15, in accordance with a non-limiting embodiment ofthe present invention. The network reference model identifies functionalentities and reference points over which interoperability is achievedbetween these functional entities. Specifically, the network referencemodel can include an SS 16, an Access Service Network (ASN), and aConnectivity Service Network (CSN).

The ASN can be defined as a complete set of network functions needed toprovide radio access to a subscriber (e.g., an IEEE 802.16e/msubscriber). The ASN can comprise network elements such as one or moreBSs 14, and one or more ASN gateways. An ASN may be shared by more thanone CSN. The ASN can provide the following functions:

Layer-1 and Layer-2 connectivity with the SS 16;

Transfer of AAA messages to subscriber's Home Network Service Provider(H-NSP) for authentication, authorization and session accounting forsubscriber sessions

Network discovery and selection of the subscriber's preferred NSP;

Relay functionality for establishing Layer-3 (L3) connectivity with theSS 16 (e.g., IP address allocation);

Radio resource management.

In addition to the above functions, for a portable and mobileenvironment, an ASN can further support the following functions:

ASN anchored mobility;

CSN anchored mobility;

Paging;

ASN-CSN tunnelling.

For its part, the CSN can be defined as a set of network functions thatprovide IP connectivity services to the subscriber. A CSN may providethe following functions:

MS IP address and endpoint parameter allocation for user sessions;

AAA proxy or server;

Policy and Admission Control based on user subscription profiles;

ASN-CSN tunnelling support;

Subscriber billing and inter-operator settlement;

Inter-CSN tunnelling for roaming;

Inter-ASN mobility.

The CSN can provide services such as location based services,connectivity for peer-to-peer services, provisioning, authorizationand/or connectivity to IP multimedia services. The CSN may furthercomprise network elements such as routers, AAA proxy/servers, userdatabases, and interworking gateway MSs. In the context of IEEE 802.16m,the CSN may be deployed as part of a IEEE 802.16m NSP or as part of anincumbent IEEE 802.16e NSP.

In addition, RSs 15 may be deployed to provide improved coverage and/orcapacity. With reference to FIG. 8, a BS 14 that is capable ofsupporting a legacy RS communicates with the legacy RS in the “legacyzone”. The BS 14 is not required to provide legacy protocol support inthe “16 m zone”. The relay protocol design could be based on the designof IEEE 802-16j, although it may be different from IEEE 802-16jprotocols used in the “legacy zone”.

With reference now to FIG. 9, there is shown a system reference model,which applies to both the SS 16 and the BS 14 and includes variousfunctional blocks including a Medium Access Control (MAC) common partsublayer, a convergence sublayer, a security sublayer and a physical(PHY) layer.

The convergence sublayer performs mapping of external network datareceived through the CS SAP into MAC SDUs received by the MAC CPSthrough the MAC SAP, classification of external network SDUs andassociating them to MAC SFID and CID, Payload headersuppression/compression (PHS).

The security sublayer performs authentication and secure key exchangeand Encryption.

The physical layer performs Physical layer protocol and functions.

The MAC common part sublayer is now described in greater detail.Firstly, it will be appreciated that Medium Access Control (MAC) isconnection-oriented. That is to say, for the purposes of mapping toservices on the SS 16 and associating varying levels of QoS, datacommunications are carried out in the context of “connections”. Inparticular, “service flows” may be provisioned when the SS 16 isinstalled in the system. Shortly after registration of the SS 16,connections are associated with these service flows (one connection perservice flow) to provide a reference against which to request bandwidth.Additionally, new connections may be established when a customer'sservice needs change. A connection defines both the mapping between peerconvergence processes that utilize the MAC and a service flow. Theservice flow defines the QoS parameters for the MAC protocol data units(PDUs) that are exchanged on the connection. Thus, service flows areintegral to the bandwidth allocation process. Specifically, the SS 16requests uplink bandwidth on a per connection basis (implicitlyidentifying the service flow). Bandwidth can be granted by the BS to aMS as an aggregate of grants in response to per connection requests fromthe MS.

With additional reference to FIG. 10, the MAC common part sublayer (CPS)is classified into radio resource control and management (RRCM)functions and medium access control (MAC) functions.

The RRCM functions include several functional blocks that are relatedwith radio resource functions such as:

Radio Resource Management

Mobility Management

Network Entry Management

Location Management

Idle Mode Management

Security Management

System Configuration Management

MBS (Multicast and Broadcasting Service)

Service Flow and Connection Management

Relay functions

Self Organization

Multi-Carrier

Radio Resource Management

The Radio Resource Management block adjusts radio network parametersbased on traffic load, and also includes function of load control (loadbalancing), admission control and interference control.

Mobility Management

The Mobility Management block supports functions related toIntra-RAT/Inter-RAT handover. The Mobility Management block handles theIntra-RAT/Inter-RAT Network topology acquisition which includes theadvertisement and measurement, manages candidate neighbor target BSs/RSsand also decides whether the MS performs Intra-RAT/Inter-RAT handoveroperation.

Network Entry Management

The Network Entry Management block is in charge of initialization andaccess procedures. The Network Entry Management block may generatemanagement messages which are needed during access procedures, i.e.,ranging, basic capability negotiation, registration, and so on.

Location Management

The Location Management block is in charge of supporting location basedservice (LBS). The Location Management block may generate messagesincluding the LBS information.

Idle Mode Management

The Idle Mode Management block manages location update operation duringidle mode. The Idle Mode Management block controls idle mode operation,and generates the paging advertisement message based on paging messagefrom paging controller in the core network side.

Security Management

The Security Management block is in charge ofauthentication/authorization and key management for securecommunication.

System Configuration Management

The System Configuration Management block manages system configurationparameters, and system parameters and system configuration informationfor transmission to the MS.

MBS (Multicast and Broadcasting Service)

The MBS (Multicast Broadcast Service) block controls management messagesand data associated with broadcasting and/or multicasting service.

Service Flow and Connection Management

The Service Flow and Connection Management block allocates “MSidentifiers” (or station identifiers—STIDs) and “flow identifiers”(FIDs) during access/handover/service flow creation procedures. The MSidentifiers and FIDs will be discussed further below.

Relay Functions

The Relay Functions block includes functions to support multi-hop relaymechanisms. The functions include procedures to maintain relay pathsbetween BS and an access RS.

Self Organization

The Self Organization block performs functions to support selfconfiguration and self optimization mechanisms. The functions includeprocedures to request RSs/MSs to report measurements for selfconfiguration and self optimization and receive the measurements fromthe RSs/MSs.

Multi-Carrier Support

The Multi-carrier (MC) support block enables a common MAC entity tocontrol a PHY spanning over multiple frequency channels. The channelsmay be of different bandwidths (e.g. 5, 10 and 20 MHz), be on contiguousor non-contiguous frequency bands. The channels may be of the same ordifferent duplexing modes, e.g. FDD, TDD, or a mix of bidirectional andbroadcast only carriers. For contiguous frequency channels, theoverlapped guard sub-carriers are aligned in frequency domain in orderto be used for data transmission.

The medium access control (MAC) includes function blocks which arerelated to the physical layer and link controls such as:

PHY Control

Control Signaling

Sleep Mode Management

QoS

Scheduling and Resource Multiplexing

ARQ

Fragmentation/Packing

MAC PDU formation

Multi-Radio Coexistence

Data forwarding

Interference Management

Inter-BS coordination

PHY Control

The PHY Control block handles PHY signaling such as ranging,measurement/feedback (CQI), and HARQ ACK/NACK. Based on CQI and HARQACK/NACK, the PHY Control block estimates channel quality as seen by theMS, and performs link adaptation via adjusting modulation and codingscheme (MCS), and/or power level. In the ranging procedure, PHY controlblock does uplink synchronization with power adjustment, frequencyoffset and timing offset estimation.

Control Signaling

The Control Signaling block generates resource allocation messages.

Sleep Mode Management

Sleep Mode Management block handles sleep mode operation. The Sleep ModeManagement block may also generate MAC signaling related to sleepoperation, and may communicate with Scheduling and Resource Multiplexingblock in order to operate properly according to sleep period.

QoS

The QoS block handles QoS management based on QoS parameters input fromthe Service Flow and Connection Management block for each connection.Scheduling and Resource Multiplexing

The Scheduling and Resource Multiplexing block schedules and multiplexespackets based on properties of connections. In order to reflectproperties of connections Scheduling and Resource Multiplexing blockreceives QoS information from The QoS block for each connection.

ARQ

The ARQ block handles MAC ARQ function. For ARQ-enabled connections, ARQblock logically splits MAC SDU to ARQ blocks, and numbers each logicalARQ block. ARQ block may also generate ARQ management messages such asfeedback message (ACK/NACK information).

Fragmentation/Packing

The Fragmentation/Packing block performs fragmenting or packing MSDUsbased on scheduling results from Scheduling and Resource Multiplexingblock.

MAC PDU Formation

The MAC PDU formation block constructs MAC PDU so that BS/MS cantransmit user traffic or management messages into PHY channel. MAC PDUformation block adds MAC header and may add sub-headers.

Multi-Radio Coexistence

The Multi-Radio Coexistence block performs functions to supportconcurrent operations of IEEE 802.16m and non-IEEE 802.16m radioscollocated on the same mobile station.

Data Forwarding

The Data Forwarding block performs forwarding functions when RSs arepresent on the path between BS and MS. The Data Forwarding block maycooperate with other blocks such as Scheduling and Resource Multiplexingblock and MAC PDU formation block. Interference Management

The Interference Management block performs functions to manage theinter-cell/sector interference. The operations may include:

MAC layer operation

Interference measurement/assessment report sent via MAC signaling

Interference mitigation by scheduling and flexible frequency reuse

PHY layer operation

Transmit power control

Interference randomization

Interference cancellation

Interference measurement

Tx beamforming/precoding

Inter-BS Coordination

The Inter-BS coordination performs functions to coordinate the actionsof multiple BSs by exchanging information, e.g., interferencemanagement. The functions include procedures to exchange information fore.g., interference management between the BSs by backbone signaling andby MS MAC messaging. The information may include interferencecharacteristics, e.g. interference measurement results, etc.

Reference is now made to FIG. 11, which shows the user traffic data flowand processing at the BS 14 and the SS 16. The dashed arrows show theuser traffic data flow from the network layer to the physical layer andvice versa. On the transmit side, a network layer packet is processed bythe convergence sublayer, the ARQ function (if present), thefragmentation/packing function and the MAC PDU formation function, toform MAC PDU(s) to be sent to the physical layer. On the receive side, aphysical layer SDU is processed by MAC PDU formation function, thefragmentation/packing function, the ARQ function (if present) and theconvergence sublayer function, to form the network layer packets. Thesolid arrows show the control primitives among the CPS functions andbetween the CPS and PHY that are related to the processing of usertraffic data.

Reference is now made to FIG. 12, which shows the CPS control planesignaling flow and processing at the BS 16 and the MS 14. On thetransmit side, the dashed arrows show the flow of control planesignaling from the control plane functions to the data plane functionsand the processing of the control plane signaling by the data planefunctions to form the corresponding MAC signaling (e.g. MAC managementmessages, MAC header/sub-header) to be transmitted over the air. On thereceive side, the dashed arrows show the processing of the receivedover-the-air MAC signaling by the data plane functions and the receptionof the corresponding control plane signaling by the control planefunctions. The solid arrows show the control primitives among the CPSfunctions and between the CPS and PHY that are related to the processingof control plane signaling. The solid arrows between M_SAP/C_SAP and MACfunctional blocks show the control and management primitives to/fromNetwork Control and Management System (NCMS). The primitives to/from MSAP/C SAP define the network involved functionalities such as inter-BSinterference management, inter/intra RAT mobility management, etc, andmanagement related functionalities such as location management, systemconfiguration etc.

Reference is now made to FIG. 13, which shows a generic protocolarchitecture to support a multicarrier system. A common MAC entity maycontrol a PHY spanning over multiple frequency channels. Some MACmessages sent on one carrier may also apply to other carriers. Thechannels may be of different bandwidths (e.g. 5, 10 and 20 MHz), be oncontiguous or non-contiguous frequency bands. The channels may be ofdifferent duplexing modes, e.g. FDD, TDD, or a mix of bidirectional andbroadcast only carriers.

The common MAC entity may support simultaneous presence of MSs 16 withdifferent capabilities, such as operation over one channel at a timeonly or aggregation across contiguous or non-contiguous channels.

Control signals, like other data, are transmitted over the wirelessmedium between the BS 14 and an SS 16 using a particular modulationscheme according to which the data is converted into symbols. A symbolis the smallest quantum of information that is transmitted at once. Asymbol may represent any number of bits, depending on the modulationscheme used, but commonly represents between 1 and 64 bits, and in somecommon modulation scheme, each symbol represents 2 bits. Regardless ofthe modulation scheme used, a single modulated symbol is sent over asingle subcarrier and generally represents the smallest quantum ofinformation that can be sent over the air interface.

A wireless communication system of the type described earlier can bedesigned to operate as a multi carrier system. A multi carrier systemdivides the spectrum in several carriers that provide differentfunctions. Two types of carriers can be defined, namely:

-   -   1. Primary carrier; this is the carrier that typically carries        the synchronization channel (or preamble), all the system        information, neighbor BS information, paging information and        resource to allocation/control information. Examples of control        information include:    -   a. Essential static system wide PHY information for decoding of        DL PHY frames/sub-frames, such as bandwidth configurations, CP        sizes, multi carrier configuration, system time, TDD ratio and        guard tones among others;    -   b. Essential pseudo-dynamic sector-side PHY information for        decoding of DL PPHY frames/sub-frames. Examples include        channelization (partitioning of diversity zone, localized zone,        pilot structure, etc), legacy/16 m resource partition, sub-frame        control configuration etc. Can also contain initial ranging        region/codes information for SS to do fast initial access        procedure;    -   c. Non-PHY system information such as BSID, operator ID and        subnet ID among others;    -   d. PHY/MAC system configuration information such as handover        parameters, power control parameters, fast feedback region and        ranging region, among others;    -   e. Neighbor BS information (c and d information about a        neighboring BS);    -   f. Paging information such as quick paging and regular paging        information;    -   g. Dynamic DL and UL resource allocation and control information        related to traffic burst assignment, such as burst assignment        related information (MCS, MIMO mode resource location, user ID,        ACK/NAK of UL traffic and UL power control among others).    -   2. Secondary carrier; this is a carrier that carries a subset of        the system information (such as information of type b above)        relating to superframe configuration on that carrier, as well as        resource allocation/control information of each sub-frame within        the carrier (such as information of the type g above). The        secondary carrier can also is convey the synchronization channel        (or preamble).

Generally, one or multiple carriers within the spectrum can bedesignated as primary carriers. Similarly, one or multiple carrierswithin the spectrum can be designated as secondary carriers. An SSinteracts with the carriers differently depending on its capability. Anarrowband SS, in other words an SS that has bandwidth capability totransmit/receive on only one carrier at a time is assigned to a primarycarrier. However, a wideband SS, in other words an SS that has bandwidthcapability to transmit/receive on multiple carriers at a time, isassigned to one or more primary carriers and can also interact with oneor more secondary carriers.

In a specific example of implementation, the primary carrier is codedivision multiplexed using a Walsh code. Pilot, paging and sync channelas defined in CDMA 2000 are transmitted on the primary carrier. Thesechannels will have the same configuration as 1XRTT overhead channels forbackward compatibility reasons. The primary carrier can be overlaid tothe existing IS95, IS95A&B and 1XRTT carriers. The primary carrier isused to provide voice and other real-time services to users. The primarycarrier can also be used to transmit MAC information to the SS.

The secondary carrier(s) are used to provide various types of dataservices to the users on the forward link. The secondary carriers can betime division multiplexed or code division multiplexed. The assignmentof the time slot or code space on the secondary carriers is transmittedby the MAC channels on the primary carriers.

When an SS that can be a mobile or fixed station performs network entry,it does so with a primary carrier of a BS. At this end, the SS will tryto determine when it enters the BS coverage region which carrier is aprimary carrier and which carrier is a secondary carrier. To allow an SSto distinguish between a primary carrier and a secondary carrier the SSis provided with logic that will identify certain characteristics of thecarriers to enable the SS to make the distinction. Several possibilitiesexist in this regard:

-   -   1. The secondary carriers are devoid of preamble or sync        channel. In this fashion, an SS will not be able to perform        synchronization with a secondary carrier. Since only the primary        carriers have a preamble or sync channel, the SS will be able to        perform synchronization with a primary carrier and perform the        network entry procedure via the primary carrier.    -   2. The secondary carrier has a preamble or sync channel.        However, one of the broadcast channels, such as the primary        broadcast channel is not present. When the SS performs        synchronization with the secondary carrier it will search for        the broadcast channels that are deemed to exist and if one or        more are missing then the SS will determine that this is a        secondary carrier. On the other hand if all the expected        broadcast channels are identified, the SS determines that it has        performed synchronization with a primary carrier and can proceed        with network entry.    -   3. The secondary carrier contains a preamble/sync channel and        all the expected broadcast channels, such as both the primary        and the secondary broadcast channel. In this instance either one        or both of the primary and secondary broadcast channels carry        control information to indicate whether the carrier is primary        or secondary. In this example, the SS will perform        synchronization with the secondary carrier and will read the        control information in the primary/secondary broadcast channel.        If the information states that the carrier is a secondary        carrier then the MS will not attempt a network entry; rather it        will continue searching for a primary carrier.    -   4. The secondary carrier contains a preamble or sync channel        that is encoded with information to indicate to the SS that the        carrier is a secondary carrier. An example of such encoding is        to provide a unique preamble sequence allowing the SS to        distinguish between a primary carrier and a secondary carrier.

FIG. 14 illustrates generally the process that is implemented by anSS/BS to perform a network entry procedure.

At the first step 1400, the SS performs a “scan” of the spectrum toidentify a primary carrier associated with the BS. In doing so, the SSmay first find a secondary carrier but that carrier is discarded byusing any one of the options discussed earlier. As soon as a primarycarrier is identified the SS will scan the broadcast channel of theprimary carrier in order to extract control information that helps theSS determining which primary carrier should be used for network entryprocedure. This is illustrated at step 1402. Since several primarycarriers are available, some of those may be better suited than others.For example, one of the primary carriers may be more loaded than anotherone and, for load balancing reasons it makes more sense for the SS toperform the network entry procedure on the primary carrier that has thelighter load.

Examples of control information that can be carried in the broadcastchannel of the primary carrier include information on the loadingcondition of the carrier, and service or QoS offered on the carrier,among others. The SS includes logic implemented in software thatexecutes on the CPU of the SS that determines on the basis of thiscontrol information if the network entry procedure should be performedon this primary carrier or on another primary carrier. The logic canwork in different ways and use different criteria for making theselection. One option is to compare the control information with certaintarget values (of QoS for example) that represent the lowest qualityconnection acceptable. If the target values are not met, the SS willdiscard this primary carrier and will continue searching for a moresuitable primary carrier.

Another possibility is to broadcast over the primary carrier controlinformation about all the other primary carriers associated with the BS,such that the SS can compare them and determine which one is best fornetwork entry and subsequent communication service.

Once a suitable primary carrier has been identified, the SS performsnetwork entry procedure. The network entry procedure is illustrated ingreater detail by the flowchart at FIG. 15. Note that some of the stepsmay be performed in part or in full during the identification of theprimary carrier to use.

The network entry procedure starts with DL synchronization step 1500during which the SS will determine the proper synchronization code touse such that it can receive data. At step 1502, the SS will extractsystem information that is transmitted by the BS. One specific exampleof system information that can be transmitted is the assignment ofspecific secondary carriers, as it will be discussed in greater detaillater. UL ranging/synchronization is performed at step 1504. Thisrequires the SS to send one or more ranging request packets that areprocessed by the BS to identify the timing of the request. The BSresponds with a ranging response packet giving time and power adjustmentinformations, among others to the SS.

Authentication and security association are established at step 1506.This process involves the data exchange allowing the BS to validate theSS and as well as setting up a secure communication link. At step 1508the SS sends information to the BS about its respective capabilitiessuch that the BS is aware as to the type of services/communicationprotocols and features that can be made available to the SS. The networkentry terminates at step 1510 where the connection with the network isnow established.

Referring back to FIG. 14, in particular to step 1404 where the BSassigns one or more of the secondary carriers to the SS. The assignmentis done by sending to the SS control information over the primarycarrier that identifies the one or more secondary carriers to be used.In one specific example, the SS will use the same timing, frequency andpower adjustments for the secondary carrier as those for the primarycarrier. In this case, the SS will not be required to perform UL rangingfor time, frequency synchronization and power adjustment purposes on thesecondary carrier. Note however, that the SS may be provided with logicto fine tune the timing/frequency synchronization/power settings on thesecondary carrier. This fine tuning operation is illustrated at step1406. The purpose is to slightly adjust those parameters to improve thedata communication parameters of the link. The fine tuning operation isdone in two steps. During the first step, the MS will performmeasurement on the preamble and/or pilot of the secondary carrier.During the second step, those measurements are processed to derivecorrection parameters that are implemented. Further measurements canthen be made to further fine tune the timing/frequencysynchronization/power. The process can be iteratively repeated as manytimes as desired.

Note that the assignment of the secondary carriers can be donestatically or dynamically. A static assignment is an assignment wherethe secondary carriers are assigned once and that assignment does notchange over time. A dynamic assignment process re-evaluates periodicallythe secondary carriers to determine of a change is required. A dynamicassignment process would be initiated by the BS which sends controlinformation to the SS to notify the SS of a change of secondarycarriers. In essence the process described at step 1404 is repeated,including the fine adjustment on the secondary carriers.

Yet another possibility to consider is for the BS to send controlinformation to force the SS to perform UL ranging with one or moresecondary carriers. This is shown at step 1408. The UL ranging processis triggered by the SS in response to control information sent by the BSover the primary carrier. The UL ranging on one or more of the secondarycarriers can be done at intervals on the basis of pre-determinedschedule. Alternatively the UL ranging can be performed only when thesecondary carriers are being assigned to the SS.

Note that the assignment process of the secondary carriers is dependenton the capabilities of the SS. For a multi-radio SS or wide band SSwhere the SS can simultaneously decode multiple carriers, the SS candecode the broadcast channels of secondary carriers or other primarycarriers. In this instance, the BS sends control information on theprimary carrier which indicates to the SS to decode the broadcastchannels of a specific set of secondary carriers.

For a single radio SS or non-contiguous spectrum, where the SS cannotsimultaneously decode multiple carriers, the BS also conveys the systeminformation about the secondary carriers to use, over the primarycarrier. The SS can then decode the broadcast channel of the secondarycarrier(s), but can operate on one carrier at a time (primary orsecondary).

This process is illustrated at FIG. 16. At step 1600, after the BS hasdetermined which secondary carriers to assign to a certain SS, the BSwill generate control information which is sent to the SS over theprimary carrier. The control information is processed by the SS at step1602. At step, 1604 the SS will start decoding the specific broadcastchannels of secondary carriers indicated by the control informationreceived.

Handover operations in the context of wireless multi carrier systems areperformed by taking into account both the primary carrier and thesecondary carriers. In the case of an intra-BS handover, where the SSwill switch from one primary carrier to another primary carrierassociated with the same BS, the process, as illustrated at FIG. 17starts by inserting control information in the primary carrier whichwill trigger the handover process. This is shown at step 1700. Intra-BShandover can be done for the purpose of load balancing for example. TheBS monitors the loading on each primary carrier and if one of theprimary carriers is near load capacity the BS instructs one or more ofthe SSs associated with that primary carrier to switch over to anotherprimary carrier. To effect the switch, the BS will insert into theprimary carrier control information that will indicate which otherprimary carrier to switch to as well as timing information specifyingthe exact moment the switch should be made.

As illustrated at step 1702, the SS will receive the control informationand process it. At the exact action time, the SS will start decoding thebroadcast channel of the target primary carrier to make the switcheffective, as shown at step 1704.

During the intra-BS handover, the SS may retain the original secondarycarrier assignment or may change it. A change may be done if there issome operational benefit to associate the SS with a new set of secondarycarriers, such as better QoS, the original secondary carriers areoverloaded, etc. If a change of secondary carriers is not required theswitch from one primary carrier to another primary carrier does notaffect the secondary carriers associated with the SS. On the other hand,if a change of secondary carriers is desirable, two options arepossible. One option is to send control information over the originalprimary carrier which indicates in addition to the target primarycarrier new secondary carriers to use by the SS. The control informationalso specifies the time at which the SS should start decoding thebroadcast channels of the new secondary carriers. In this fashion, atthe exact action time the SS starts decoding the broadcast channel ofthe target primary carrier and the broadcast channels of the secondarycarriers.

Another possibility is to effect the secondary carrier switch in twosteps, first by switching the primary carrier and once the SS startsreceiving control information over the target primary carrier, thenperform the secondary carrier switch. More specifically, controlinformation is sent over the newly acquired primary carrier whichindicates which are the secondary carriers to use. Note that a switch ofsecondary carriers may include a switch of all the secondary carriers(when the SS is associated with a plurality of secondary carriers) or achange of only one secondary carrier while another secondary carrierremains unchanged.

In the case of an inter-BS handover the entire set of carriers, namelythe primary carrier and the secondary carriers are switched to a newprimary carrier and a secondary carrier of the new BS. To facilitatethis process, the currently serving BS broadcasts/multicasts/uncasts theneighboring BS multi-carrier configuration information to the SS. The SSwill process the information, store it and when the handover isinitiated use the information to connect with the primary and secondarycarriers of the new BS.

The sleep mode operation management in a multi carrier environment isillustrated at FIG. 18. When the SS is in a sleep mode it follows a setof predetermined sleep mode parameters, which define a sleep windowduring which the SS is not listening and a listening window in which theSS is listening for traffic indication. As shown at step 1800, the BSwould notify the SS that it has traffic scheduled for it by placing apositive traffic indication in a listening window. The listening windowis implemented over the primary carrier. The SS monitors the listeningwindow and goes to sleep during the sleep window.

At decision step 1802, the logic processing the contents of thelistening window determines if it contains a positive traffic indicationfor the SS. In the negative, the process returns to step 1800 to monitorthe contents of the next listening window.

If a positive traffic indication is identified, the SS processes thedata to determine over which carrier the data traffic is expected tooccur. This is shown at step 1804. The data traffic indication mayindicate that the data traffic will occur over the primary carrier orover a secondary carrier. The mobile will then monitor the designatedcarrier to extract the data traffic. This is shown at step 1806.

The idle mode operation is the same for a single carrier and a multicarrier environment. The BS derives for the SS idle mode parameters thatinclude a paging listening window configuration and a paging unavailablewindow configuration. During the paging listening window, the SSmonitors the paging indication and message on the primary carrier. Whenpaged, the SS performs a network re-entry procedure on the primarycarrier.

FIGS. 19, 20 and 21 illustrate different examples of a channel qualityfeedback procedure in a multi carrier environment. FIG. 19 illustrates afirst example in which the SS reports Channel Quality Information (CQI)of a secondary carrier. In this case, the secondary carrier is notassigned a UL feedback control channel so the CQI is reported over acarrier other than the one which is being monitored. The SS determinesthe CQI in connection with the secondary carrier of interest, as shownat step 1900 and transmits the CQI through the UL feedback controlchannel over the primary carrier. This is illustrated at step 1902. TheCQI transmission includes an identification of the secondary carrier forwhich the reporting is being done such that the BS can adequatelyidentify the carrier upon receipt of the CQI information.

FIG. 20 illustrates another example of implementation. In this examplethe BS assigns at step 2000 a UL feedback control channel to thesecondary carrier associated with the SS. At step 2002 the SS determinesthe CQI associated with that secondary carrier and transmits it to theBS over the UL feedback control channel, as shown at step 2004. Notethat when several secondary carriers are assigned to the SS, the sameprocess can be replicated in connection with each secondary carrier,namely each secondary carrier is assigned a UL feedback control channeland the CQI of each secondary carrier is forwarded to the BS over therespective UL feedback control channel.

FIG. 21 illustrates yet another example of channel quality feedback. Inthis instance the BS assigns a UL feedback control channel in connectionwith a subset of secondary carriers. In other words, one UL feedbackcontrol channels is assigned the task of carrying CQI relating toseveral secondary carriers. This is shown at step 2100. At step 2102 theSS will generate CQI values for each of the secondary carriers on whichfeedback is to be provided. The set of CQI values is packaged and sentover the BS through the assigned UL feedback control channel, as shownin step 2104. The packaging involves associating with each CQI value atag or any other identifier that would allow the BS to associate theparticular CQI value with the proper secondary carrier.

The UL feedback control channel can be implemented on the primarycarrier m or on the secondary carrier. Alternatively more than one ULfeedback control channel can be provided.

Multi-Carrier Operation

The present disclosure describes multicarrier operation for networkentry, system information acquisition, handover, sleep mode, idle mode,channel quality feedback.

Network Entry Operation

In some implementations, a mobile station (MS) performs network entrywith a primary carrier of a BS. A MS needs to know which carrier(s) ofthe BS are primary carriers. There are 4 possible options that allow theMS to detect which carrier(s) are primary carriers. Option 1: secondarycarrier may have no preamble or sync channel. In such a case, the MS maynot be able to perform synchronization with a secondary carrier andtherefore may not proceed with network entry procedure with a secondarycarrier. Option 2: secondary carrier contains preamble or sync channel.However, one of the broadcast channel (e.g. the primary broadcastchannel) is not present. When MS does not detect the primary broadcastchannel, the MS knows that this is a secondary carrier and may notproceed with network entry procedure with that carrier. Option 3:secondary carrier contains preamble/sync channel, and all broadcastchannels (e.g. both primary broadcast channel and secondary broadcastchannel). The primary broadcast channel or secondary broadcast channelcontains control information that indicates whether the carrier is aprimary or secondary carrier. Option 4: secondary carrier containspreamble or sync channel. Different preamble sequence is used toindicate if the carrier is a primary carrier or secondary carrier.

To facilitate the MS to select which primary carrier to perform networkentry procedure, the broadcast channel transmitted on a primary carriercan carry information that helps the MS make the selection. Suchinformation includes loading condition on the carrier, service or QoSoffered on the carrier etc. MS enters the network through primarycarrier. BS either semi-statically or dynamically assigns secondarycarrier(s) via control signaling through primary carrier. MS may omit ULranging (for time/frequency synchronization and power adjustmentpurpose) with secondary carrier. In this case, MS uses the same timing,frequency and power adjustment information for the secondary carrier asin the primary carrier. The MS may perform fine timing/frequency/poweradjustment on the secondary carrier through measuring the preambleand/or pilot on the secondary carrier. BS may instruct the MS, throughcontrol signaling on the primary carrier, to perform UL ranging with oneor more secondary carriers.

In both single carrier and multi-carrier operation, the MS network entryprocedure can be simplified to the following:

DL synchronization

Obtain system information

UL ranging/synchronization

Authentication/security association establishment

Capability negotiation and registration

Connection establishment

Obtaining System Information of Secondary Carriers

In some implementations, for a multi-radio MS or wideband MS where theMS can simultaneously decode multiple carriers, the MS can decode thebroadcast channels of secondary carriers or other primary carriers. BSmay instruct the MS, through control signaling on the primary carrier,to decode broadcast channels of specific set of secondary carriers.

For single radio MS or non-contiguous spectrum, where the MS cannotsimultaneously decode multiple carriers, the BS can convey the systeminformation of secondary carriers to MS, through control signaling onthe primary carrier.

Handover Operation

In an intra-BS handover, the BS may instruct the MS, through controlsignaling on the current primary carrier, to switch/handover to anotherprimary carrier within the same BS for load balancing purpose or otherreasons. In such a case, the MS just switches to the target primarycarrier at action time specified by the BS. There is no need forhandover re-entry procedure (i.e. ranging, network re-entry).

In an inter-BS handover, to facilitate MS′ scanning of neighbor BS′primary carriers, the current serving BS may broadcast/multicast/unicastthe neighbor BS′ multi-carrier configuration information to the MS.

Sleep Mode Operation

One set of unified sleep mode parameters (i.e., sleep window andlistening window configuration) are configured for a MS regardless ofsingle carrier or multi-carrier operation. During listening window, MSmonitors the traffic indication on the primary carrier. If trafficindication is negative, MS goes back to sleep. If traffic indication ispositive, MS continues to monitor the primary carrier control channel toknow if it has traffic scheduled for transmission on the primary carrierand/or secondary carrier.

Idle Mode Operation

One set of unified idle mode parameters (i.e., paging listening windowand paging unavailable window configuration) are configured for a MSregardless of single carrier or multi-carrier operation. During paginglistening window, MS monitors the paging indication and message on theprimary carrier. When paged, the MS perform network re-entry procedurewith the primary carrier.

Channel Quality Feedback

Option 1: MS transmit the channel quality information (CQI) of asecondary carrier through the UL feedback control channel on the primarycarrier. Option 2: MS is assigned UL feedback control channel on asecondary carrier. MS transmits the CQI of the secondary carrier throughthe assigned UL feedback control channel on that carrier. Option 3: MSis assigned UL feedback control channel on a subset of secondarycarriers. MS transmits the CQI of a number of secondary carriers (asinstructed by the BS) through the assigned UL feedback control channelson the primary carrier and a subset of the secondary carriers.

High Level Structure of MC-DV (Multi-Carrier—Data and Voice)

Carrier Structures

On the forward link, N×1.25 MHz carriers (N>=3) can be configured forthe MC-DV system. The chip rate of each carrier is operated at 1.2288Mbps. The configurations of these carriers are defined as follows: Oneor more primary carrier is defined in a MC-DV system. The primarycarrier is code division multiplexed using Walsh code. Pilot, paging andsync channel as defined in cdma2000 are transmitted on the primarycarrier. These channels will have the same configuration as 1XRTToverhead channels for backward compatibility reasons. The primarycarrier can be overlaid to the existing 1S95, 1S95A&B and 1XRTTcarriers. The primary carrier is used to provide voice and otherreal-time services to the users. The primary carrier can also be used totransmit medium access control (MAC) information to the mobile station.

The supplemental carrier(s) are used to provide various types of dataservices to the users on the forward link. The supplemental carriers canbe time division multiplexed or code division multiplexed. Theassignment of the time slot or code space on the supplemental carriersare transmitted by the MAC channels on the primary carriers.

Channel and Frequency Assignment

1 to N carriers can be assigned to one or a group of users to transmitand receive data on forward and reverse link. FIGS. 22(a) to 22(d) areexamples of different configurations. Please note that this inventiondoes not preclude other forward and reverse carrier assignmentconfigurations. For example, when only one carrier is used, this carrierdoes not need to be always in the center of the 3-carrier group.

The following describes the forward link operations. When connected, thebase station directs each mobile station to perform the C/I estimationof M (M<=N) carriers periodically. Upon receiving the feedback, the basestation schedules target mobile station, the carrier assignment and thetransmission data rate for each time slot or code space based on thechannel condition and the type of services of the targeted user, as wellas the loading condition on different carriers. Mobile station detectsthe assignment from the MAC channel and receives the transmission slotsaccordingly.

Adaptive Modulation and Coding Across Different Carriers for ForwardLink

The base station schedules the transmitted frequency carriers, thepayload size, the modulation and the coding schemes of each burst tousers according to the channel estimation from each mobile stations andthe type of services of each user.

Different modulation and coding scheme for different carriers can beassigned to each user. For instance, the user may be assigned on onlyone carrier for the data burst. This happens probably because there is abig difference between the channel conditions on different carriers,thus the base station selects to transmit to the target user only on thecarrier with the best channel condition to improve the overall systemthroughput. The user may also be assigned on more than one carriers forthe data burst. This happens probably because the channel conditionsamong different carriers are relatively same. Thus the base station willtransmit on multiple carriers to benefit from frequency diversity. Inaddition, the loading condition of different carriers may also influencebase station's decision of carrier assignment.

When transmitted on different carriers simultaneously to the same userfor the same packet, a generic coding and punctuation scheme isemployed. The packet will be coded by Turbo code with a base codingrate. Then coded bits will be divided into sub-code blocks. The numberof sub-code blocks corresponds to number of carriers assigned. The blocksize of different sub-codes may not be the same due to the possibilityof different modulation schemes on different carriers.

Retransmission on Different Carriers for Forward Link

MC-DV uses physical layer HARQ to improve the performance. Uponreceiving each packet, the mobile station transmits ACKINAK feedback tothe base station. The base station then transmits the redundancy bits tothe mobile station. The base station selects the designated carriers,the coding and modulation schemes of the retransmission packetsaccording to mobile station's feedback on channel estimations at thetime of retransmission. The sequence number in the MAC channelassignment informs the mobile station that it is a redundancytransmission.

Service-Driven Protocol Design

Overall Protocol Structure

As described in previous sections, the physical layer resourceassignment to each mobile station is performed according to the radiochannel condition experienced in the forward link of the mobile station;as well as service requirements which are defined by upper protocollayers, i.e. air-interface protocol layer 2 and 3. The physical resourcecan be divided into two domains: frequency domain in terms ofcarrier(s); and time domain in terms of time slot(s). We propose aversatile service-driven protocol design consists of a common layer 2and layer 3 protocol stack as shown in FIG. 23, to support multiple,inhomogeneous carriers and physical layer configurations. The layer 2and 3 protocols provide a common interface with the wireline upper layerprotocols such as PPP/IP/TCP. The layer 2 and 3 protocols interface withthe multi-mode physical layer by selecting the appropriate physicallayer resource in both frequency domain and time domain to meet thequality of service required by upper layers applications as well as thesubscriber's profile. One possible implementation of the protocol layersis shown in FIG. 23, where centralized L2/3 is implemented in the basestation controller (BSC), distributed layer 2/3 is implemented in thebase station subsystem (BTS) controller, and the different physicallayer configurations are implemented in the BTS′ modem. This inventiondoes not preclude any other forms of implementation that realize themulti-carrier protocol structure proposed herein. The multi-modephysical layer consists of 1 to N carriers, where each of the carriercan be configured differently in terms modulation and coding schemes, asdescribed in previous sections. Each of the carrier can also beconfigured differently in terms of the QoS or the set of QoSs itprovides to the upper layers. The layer 2 protocol consists of the oneor more Radio Link Protocols (RLPs) and one or more Medium AccessControl (MAC) sublayer. Alternatively, QLP (QoS Link Protocol, to bedescribed later), may be used instead of RLP. RLP provides transparent(no ARQ) or non-transparent (with ARQ) link layer control. The dataplane of the MAC sublayer provides dynamic multiplexing anddemultiplexing of layer 2 frames from one or more users or terminalsto/from physical layer frames. The control plane of the MAC sublayerconsists of a MAC state machine per user/terminal. The layer 3 protocoldefines a set of signaling messages and signaling flows that controlsthe overall air-interface operations.

Layer 2/3 and Physical Layer Interface

We propose the following protocol interface between layer 2/3 andphysical layer, as shown in FIG. 24. The physical layer resource aspresented to layer 2/3, is defined as consisting of a set of resourcepools. Each of the resource pool is uniquely defined based on thefollowing parameters:

Quality of service supported which may include, but not restricted to,data rate (minimum, maximum, mean), service type such as real-time ordelay tolerant service

List of manageable resources such as time slots, spreading codes, power,modulation and coding set

Carrier Identification

Air-interface configuration, such as IS-95, 1xRTT, 1xEV-DO or other newconfigurations

Please note that one or more resource pools may reside on the samecarrier. On the other hand, a resource pool may consist of multiplecarriers. A mobile station can use one or more resource pools at anyparticular instance. Layer 2/3 performs fast and dynamic management ofthe physical layer resource, defined as a set of resource pools, to meetupper layers service requirements and resource availability at eachpool. Resource availability of each pool can be dynamically affected bythe loading and the forward link channel condition experienced by themobile station at the particular pool. A centralized resource controlperforms call admission, slow quasi-static, time-of-day management ofthe pools' characteristics and boundaries.

The following describes one implementation of the resource poolsconfiguration in the forward link:

Resource Pool #1:

-   -   primary carrier #1    -   IxRTT backward compatible    -   manageable resource Walsh codes, forward power    -   service characteristics: real-time voice service

Resource pool #2:

-   -   primary carrier #1    -   IxRTT backward compatible    -   manageable resource Walsh codes, forward power    -   service characteristics: real-time data service

Resource pool #3:

-   -   supplemental carrier #2    -   Non backward compatible. New physical layer (AMC etc.).    -   Manageable resource: time slots    -   service characteristic: delay tolerant service

Resource pool #4:

-   -   supplemental carrier #3    -   Non backward compatible. New physical layer (AMC etc.).    -   Manageable resource: time slots    -   service characteristic: delay tolerant service

QLP (ODS Link Protocol)

In additional to the traditional, backward compatible RLP, a new QLP isintroduced: Each user typically has one QLP instance, although more thanone QLP per user is also allowed.

Each QLP can support to up to 4 streams of user data/applications.

QLP accepts two types of data stream.

-   -   PPP over HDLC for efficient over the air delivery.    -   Individual IP packets. IP AL (filed separately) is used for zero        padding and multiplexing small packets if needed.

QLP employs fixed size PDU, which can be N times of QLP Base_Size. TheQLP Base_Size is small enough for efficient VoIP transmission.

QLP uses QLP packet count instead of data octets count as sequencenumber.

QLP may employ different ARQ mechanism (NAK or ACK) or no ARQ at all(for voice) for each stream of data.

Each QLP PDU carries a priority indicator. The value of this priorityindicator is set according to a set of QoS requirements:

-   -   User's overall QoS class    -   Application's QoS requirements    -   Current data transmission condition (e.g., it could be a        function of the number of QLP packets in the transmission buffer        waiting for transmission or the average data throughput. The        priority may be increased/decreased accordingly to maintain the        data rate and/or packet delay)    -   Scheduler feedback (e.g., scheduler may request all QLP to lower        the priority of its low QoS class packet when its resource is        running tight)

Scheduling

The following dynamic management of physical layer resource at the basestation is proposed:

Each user may have access to both dedicated channel(s) and sharedchannel(s). These channels may be power controlled or rate controlled.

For each packet, layer 2/3 decides which pool or pools it should besent, based on call setup service configuration), and based on thepacket's QoS priority.

The scheduler may actively manage the QoS priority for packets waitingin its transmission queues. And a packet originally assigned for sharedchannel transmission may be switch over for dedicated channeltransmission if the packet has been waiting for too long or if theshared channel cannot meet its QoS requirement)

Layer 2/3 scheduler decides which packet should be sent based on thefollowing parameters (please note that other parameters are notprecluded by this disclosure):

-   -   time-to-live (applicable for pseudo-real-time service only)    -   relative users' priority (applicable for deployment scenario        where ‘absolute’ QoS is not defined)    -   guaranteed minimum average data rate    -   channel condition feedback from the mobile station    -   the capacity cost of each RF channel

Reverse Link

In some implementations, MC-DV reverse link operates as following:

Active Mode

Reverse link frame size is 10 ms or 5 ms, in order to take advantage ofmulti-user diversity. It can't be too small because of no accurate timesynchronization.

Before mobile station starts to transmit, it sends outR_DataRateRequest. Mobile station calculates R_DataRateRequest based onthe its current pilot transmission power (since the reverse link ispower controlled, the current transmission power basically acts as DRCfeedback for base station), active set (for active set>1, themax_R_DataRateRequest is significantly restricted) and service needs.

Upon receiving the R_DataRateRequest, the base station grants thetransmission of the mobile station at the next slot by sends out its MACID on RL_ASSIGNMENT_CH. The RL_ASSIGNMENT_CH may have more than one MACID at the same slot. (may use Qualcomm's idea for different long codemask instead of MAC ID) For mobile station in soft handoff, mobile willtransmit if anyone base station assigns it.

During the transmission, a RL_RATE_CONTROL_CH controls the up/down ofthe transmission rate for each mobile station. For mobile in softhandoff, it use or of downs.

Retransmission

H-ARQ is employed on reverse link. RL_ARQ_CH is transmitted on theforward link to send ACK/NAK. Sub-code is used for incrementalredundancy. RL_ARQ_CH, RL_RATE_CONTROL_CH and RL_ASSIGNMENT_CH can becombined into one RL_MAC_CH.

MAC State Machine

We propose the following overall MAC states for the control plane ofeach user: Active state, Standby state, Dormant state and Nun state. For1xRTT terminals, the standby state will be bypassed.

To support the standby state in MC-DV system, the paging channels can besplit into two groups (refer to FIG. 25). The first group which is theGeneral Paging channels has the same functionality as in 1XRTT, to pageusers in dormant state. The second group which is the Standby Pagingchannel, is used to page standby state users only.

In the active state, the mobile monitors the dedicated or common controlchannel on the primary carrier for control information to receive dataover the traffic channel(s) in the primary and/or supplementalcarrier(s).

In the standby state, a mobile monitors Standby Paging channelperiodically. In this state, a mobile monitors only the primary carrierfor possible paging message. To support fast state transition, themonitoring cycle can be flexibly configured, e.g., Sms, 10 ms, 20 ms, orK*20 ms (K is an integer number). To decrease interference of thisStandby Paging channel, blind rate detection at the mobile or DTX modecan be supported. To decrease overhead caused by paging standby users, ashort paging message is designed which includes a Standby user ill and apointer. This pointer introduces the mobile to an appropriate controlchannel for subsequent resource assignment.

802.16M Control Framework

The application proposes the different aspects of control signalingmechanism between BS and MS to support system operation including systemconfiguration, resource allocation/control, paging, MS network entry,power saving modes, multi-carrier operation. The proposed scheme allowsreduced control overhead, enables power saving reduces MS processingrequirements and enables MS fast network entry.

To reduce the broadcast control signaling overhead, we propose the BS totransmit static systemwide information, only when the BS detects thatthere is MS attempting to enter the network. There are two general typesof static system wide information. One is essential physical layerconfiguration information that is needed for initial system access.Second is MAC/upper layer information that is not needed for initialsystem access. For the former, the BS has to broadcast the informationonce it detects that there is one or more MSs attempting network entry.For the latter, the BS unicasts the information the MS after the MS hasperformed mitial system access.

In order for the BS to detect if there is one or more MSs attempting toenter the network, the BS broadcast the uplink ranging (or randomaccess) information periodically so that MS attempting network entry candecode such information and use it for transmitting up ink ranging(random access).

Since different types of control signaling, e.g. system configurationbroadcast, paging, resource allocation/control, should be sent atdifferent periodicity and some are event driven (e.g. paging informationdoes not have to be sent if there is no MS to page), we propose tosignal the presence of a particular type of control information using aBroadcast Pointer Channel (BPCH). An MS only needs to decode the BPCH tofind out if it needs to decode subsequent control channels. This enablepower saving. To further reduce overhead BPCH may not be present inevery frame. We propose two options for MS to detect whether BPtH ispresent or not. One option is MS performs blind detection on thepresence of BPCH. Second option is the presence of BPCH is indicated bya flag in the multicast control segment (MCCS), where MCCS is a segmentthat is already present in every frame for the purpose of resourceallocation/control.

As it is critical for MS to receive system configuration informationsent by the BS, we propose schemes to enable MS to track whether it hasthe most up to date system configuration information sent by the BS. Theschemes proposed also enable power saving of MS in normal mode, sleepmode and Idle mode. We propose the overall MS network entry procedurebased on the components listed above. For the case of multi-carrierdeployment, a wideband MS can be instructed by the BS to monitor asubset of the carriers for control information, for power savingpurpose, reduce processing requirements, as well as reduce systemcontrol signaling overhead. We propose primary and secondary carrierswhich carry different types of control information.

This contribution presents the types of control information required for802.16m system operation including system access, transmission/receptionof traffic packets, handover etc. Different types of control informationhas different characteristics in terms of the frequency of change,broadcast or unicast, robustness requirement, importance to initialsystem access, etc. Therefore, different types of control informationshould be treated differently. This contribution presents how each typeof control information should be transmitted by the BS and received bythe MS. A description of the MS network entry procedure as well as sleepmode operation are provided in terms of how the MS obtains the necessarycontrol Information for proper operation. The support of multi-carrieroperation is also described in terms of how MS monitors each carrier forthe necessary control information.

Control Information in Legacy 16E System

In 16e, scheduling control information is sent in MAPs, while systeminformation is sent in DCD/UCD. In addition, neighbor BS information andpaging information are sent on broadcast MAC messages. Some of theinformation sent on MAPs are not necessary dynamic and therefore can besent in less frequent manner to reduce overhead. E.g., STC zone switchIE, ranging region definition, fast feedback region definition. Some ofthe information in DCD/UCD are static system information, thus does notneed to be periodically broadcast to MSs that have already entered thenetwork or broadcast with a relatively long period to improvereliability. E.g., BS 10, operator 10, subnet 10, TDD ratio. Some of theinformation in DCD/UCD are semi-static system configuration information,thus does not need to be periodically broadcast to MSs that have alreadyentered the network if the configuration hasn't been changed orbroadcast with a relatively long period to improve reliability (e.g.,burst profile, handover parameters). Similarly, neighbor BS informationwhich is semi-static information does not need to be periodicallybroadcast to MSs that have already entered the network if theconfiguration hasn't been changed.

TABLE 1.1 TYPES OF DL CONTROL INFORMATION Control information typeExamples Characteristics Control channel design 1) Essential staticBandwidth Static system-wide Information should be systemwide PHYconfigurations, CP deployment specific broadcast either a) informationfor sizes, multi-carrier parameters. Required for fast periodically orb) initial decoding of OL configuration, initial access during networkranging event. If case a), PHY frames/sub- system time, TOO entry. MSshould be able to these information should be frames ratio, guard tones.decode these information carried in a fixed resource aftersynchronization location within a superframe. In case b), thepresence/absence of the information is signaled by a Broadcast PointerChannel (BPCR). Information should be delivered with very highreliability. 2) Essential Channelization Information can change fromInformation should be pseudodynamic (partitioning of one superframe toanother. broadcast periodically every sector-wide PHY diversity zone,Required for fast initial superframe. These information for localizedzone, pilot access during network entry information should be decodingof OL structure etc.), and handover. MS should be carried in a fixedresource PHY frames/sub- legacy/16 resource able to decode theselocation within a frames (i.e., partition, subframe information aftersuperframe. Information superframe control synchronization and should bedelivered with configuration configuration etc. information in 1). veryhigh reliability. control Can contain initial information) rangingregion/codes information for MS to do fast initial access 3) Non-PRYProcedure. BSID, Static system information Since information is static,it system operation ID, sub doesn't have to be information net ID etcperiodically broadcast to MSs. It can be sent by unicast to a MS duringinitial network entry. These information does not have to be carried infixed resource location. 4) PRY/MAC Handover Semi-static system For MSalready entered the system parameters, power configuration information,network, there is no need to configuration control parameters,Configuration parameters broadcast the information in information fastfeedback region, values can change in a slow frequent configurationranging region etc. fashion (on order of parameters, if theseconds/minutes/hours). information hasn't changed. The control channeldesign should support efficient power saving for sleep mode and idlemode MS while ensuring any changes in the system configuration isreceived by the MS in timely fashion. For MS performing initial networkentry, the system configuration information is sent as unicast messageto the MS during network entry procedure to expedite the network entry.Note that BS has to already completed initial ranging procedure with MS.Details of the design to transmit this type of information is given inslides 10-12. 5) Neighbor BS Information types 3) As indicated inprevious Information can be broadcast information and 4) of neighborslide for type 3) and 4) periodically or event BSs triggered. Theinformation can also be unicast to MS who wants to add a neighbor BS tothe active set. 6) Paging Quick paging and Non-periodic information.Information should be information regular paging Event driven broadcastwhenever there is information one or more MS to page. 7) Dynamic DLBurst assignment Dynamically changes Control information is and ULrelated information: every sub-frame unicast if the traffic burst isresource MCS, MIMO mode, unicast. Control information allocation andresource location, is multicast/broadcast if the control user ID trafficburst is information ACK./NAK of UL multicast/broadcast/ related traffictraffic UL power Resource location indication burst assignment controlis multicast.

Broadcast Pointer Channel (BPCH)

The broadcast of Information types (1), (3), (4), (5), (6) may or maynot be present in a sub-frame or superframe boundary. To efficientlyindicate the presence/absence of these information block, a 16 mBroadcast Pointer Channel (BPCH) is introduced.

The 16 m BPCH contains the following: information blocks presence flags,length of each information block that is present. Examples ofinformation blocks are: System information, types (1); (3), (4), (5). Inthis information block, multiple MAC management messages for thedifferent information types can be encapsulated. Paging information(type (6)) (either quick paging or full paging information).

One benefit of 16 m BPCH is to allow sleep mode and idle mode MS to onlydecode the 16 m BPCH to find out if broadcast information is present andwhether the broadcast information present is relevant or not (e.g.paging information is not relevant to sleep mode MS). If the broadcastinformation is not present or the broadcast information not relevant,the MS can go back to sleep without the need to decode the rest of thesub-frame and the resource allocation/control information, i.e. type(7). If the broadcast information is present and relevant, the MS justneeds to decode the relevant broadcast information and go back to sleepwithout the need to decode the rest of the sub-frame and the resourceallocation control information, i.e. type (7).

BPCH mayor may' not be present in each sub-frame. There are two optionsof how the presence of BPCR can be detected. Option 1: A ‘BPCH present’flag is added to the multicast control segment (MCCS) to indicate thepresence/absence of the BPCH. Note that MCCS contains controlinformation to indicate the partitioning of resource within a frame fortraffic bursts. MCCS is of fixed length and modulation/coding (refer tocontribution NNN for details). An MS first decodes the MCCS. If the‘BPCH present’ flag is set to ‘1’ (i.e. BPCH is present), the MS willdecode the BPCH. The length and modulation/coding of BPCH is fixed. Theinformation contained in BPCH will allow the MS to decode the systembroadcast information that follows. The remaining resource in thesub-frame is for traffic burst and the partitioning of those resourcesis signaled by the MCCS. If the ‘BPCH present’ flag is set to ‘0’ (i.e.BPCH is not present), the MS will know that both BPCH and systembroadcast information are not present. The remaining resource in thesub-frame is for traffic bursts, and the partitioning of those resourcesis signaled by the MCCS. Option 2: If present, BPCH is located at fixedlocation in a sub-frame. It has fixed length and modulation/coding. MSperforms blind detection to decide if BPCH is present or not. An MSfirst attempts to decode BPCH. If decoding successful, the informationcontained in BPCH will allow the MS to decode the system broadcastinformation that follows. The remaining resource in the subframecontains the MCCS and resource for traffic bursts. The partitioning ofthe resource for traffic burst is signaled by the MCCS. Note that MCCSis of fixed length and modulation/coding. If MS does not successfullydecode the BPCH, the MS will assume that both BPCH and the systembroadcast information are not present. The MS proceeds to decode theMCCS and the rest of traffic burst if applicable.

Transmission of System Configuration Information

As this type of information is semi-static and can change, the BS has toinform the MS in a timely manner when the information changes whileenabling power saving of MS. In one implementation, a ‘systemconfiguration change count (SCCC)’ is included in the systemconfiguration broadcast messages sent from the BS. It is used toindicate the version number of the associated system configurationinformation. An action timer is included in the systemconfiguration-broadcast messages to indicate when the associated systemconfiguration takes effect. Overall, an MS stores up to two sets of SCCCvalues and corresponding system configuration information in its memory.One is the SCCC value and corresponding system configuration informationcurrently in effect. The other is the SCCC value and correspondingsystem configuration information that will take effect at a specificaction time. BS transmits a SCCC and a ‘system configuration changealert (SCCA), flag periodically in a frequent manner. For example, everysuperframe as part of the superframe configuration control information,i.e. type (2). The SCCC is used to indicate the version number of thesystem configuration information currently in effect. The SCCA flag isused to indicate if BS has broadcast new system configurationinformation than those associated with the current SCCC.

By detecting the SCCC value, the MS knows the current version of thesystem configuration information in effect and therefore can configureitself accordingly if the MS has previously received the correspondingsystem configuration broadcast messages. By detecting the SC A flag, theMS knows if BS has broadcast new system configuration information. Ifthe flag is set to ‘1’ 1 the MS will try to decode the systemconfiguration broadcast messages in current and subsequent subframesuntil It has successfully decoded the information. ⋅If MS has detectedan SCCC value from the BS that is different from the SCCC value(s) theMS has stored, the MS shall cease UL transmission and attempt to decodesystem configuration broadcast messages from the BS in the downlink. TheMS shall only resume UL transmission after it has successfully decodedthe system configuration broadcast messages that contain the SCCC value.⋅To support power saving for MS in normal/active mode: ⋅If MS hasdetected that SCCC value has not changed and SCCA flag is set to ‘0’,the MS does not need to decode the system configuration broadcastmessages indicated in the BPCH ⋅If MS has detected that SCCC value hasnot changed and SCCA flag is set to ‘1’ and if the MS has previouslysuccessfully decoded the system configuration broadcast messages withnew SCCC value, the MS does not need to decode the system configurationbroadcast messages indicated by the BPCH ⋅If MS has detected that SCCCvalue has not changed and SCCA flag is set to ‘1’ and if the MS has notpreviously successfully decoded the system configuration broadcastmessages with new SCCC value, the MS has to decode the systemconfiguration broadcast messages indicated by the BPCH.

To support power saving for MS in sleep mode or idle mode: BSperiodically transmit the system broadcast information. MS in sleep modeor idle mode wakes up periodically (with period configured by the BS) toattempt to decode the SCCC/SCCA sent in the superframe configurationcontrol information. The wake-up time of the MS should co-inside withthe time when the SCCC and SCCA is broadcast by the BS. If the MSdetects that SCCC has changed and the value is not the same as what itstores in the memory the MS shall be awake in this subframe andsubsequent sub-frames to decode DPCH and the system broadcastinformation until it has successfully decode system configurationbroadcast messages from the BS that contains the SCCC value. If the MSdetects that SCCC has not changed but SCCA flag is set to ‘1’ and the MShas not previously received system configuration broadcast messages fromBS that contains a new SCCC value, the MS shall be awake in thissubframe and subsequent sub-frames to decode BPCH and the systembroadcast information until it has successfully decode systemconfiguration broadcast messages from the BS that contains a new SCCCvalue If the MS detects that SCCC has not changed and SCCA flag is setto ‘0’, the MS can go back to sleep (if it is in sleep window or pagingunavailable interval) without the need to decode the subsequentsub-frames.

Initial Network Entry Procedure at MS

There are two methods for MS network entry procedures which correspondto the two options for the type (1) in Table 1.1. Method 1 is based onoption (1a) of type (1) information: MS synchronizes with syncchannel/preamble. MS decodes information type (1). MS decodesinformation type (2). MS performs UL ranging procedure based on theranging region information given in information type (2). MS obtainstype (3) and type (4) information through unicast signaling from the BS,transmitted on DL PHY sub-frames.

Method 2 based on option (1b) of type (1) information: MS synchronizeswith sync channel/preamble. MS decodes information type (2) and obtainthe ranging region information. MS performs UL ranging procedure basedon the ranging region information given in information type (2). BSdetects the MS ranging attempt, and BS transmits the information type(1). MS decodes the information type (1). MS continues the rangingprocedure. MS obtains type (3) and type (4) information through unicastsignaling from the BS, transmitted on the DL PHY frames.

Multi-Carrier Support

In the case of contiguous spectrum, multi-carrier mode is used tosupport MSs with different bandwidth capability. For example, a 10 MHzspectrum can be divided into two 5 MHz carriers in order tosimultaneously' support MSs with 5 MHz bandwidth capability and 10 MHzbandwidth capability. Not all the carriers need to carryall the systembroadcast information as system-wide and sector-wide system Informationare common to all carriers. Repeating the information over multiplecarriers increases the overhead. Two types of carriers can be defined: ePrimary carrier: this is a carrier that carries the synchronizationchannel (or preamble), all the system information, neighbor BSinformation, paging information and resource allocation/controlinformation, i.e information type (1) to type (7) described in slides3-5. Secondary carrier: this is a carrier that carries a subset of thesystem information, i.e, information type (2) for information related tosuperframe configuration on that carrier; as wen as the resourceallocation/control information of each sub-frame within the carrier,i.e. type (7). This type of carrier may also carry the synchronizationchannel (or preamble).

One or multiple carriers within the spectrum can be designated asprimary carriers. One or multiple carriers within the spectrum can bedesignated as secondary carriers. A narrowband MS, i.e. an MS that hasbandwidth capability to transmit/receive on only one carrier at a time,is assigned for a primary carrier. A wide band MS, i.e., an MS that hasbandwidth capability to transmit/receive on multiple carriers at a time,is assigned to one or multiple primary carriers. A wideband MS monitorsonly the assigned primary carrier(s) for system broadcast information,i.e. type (1) to type (6), and resource allocation/control information,i.e. type (7), for new traffic packet transmission. The wideband MS alsomonitors secondary carrier(s) for superframe configuration broadcastinformation, i.e. type (2) at the superframe boundary. The MS maymonitor the resource allocation/control information, i.e. type (7), onsecondary carrier(s) for HARQ retransmissions. Details of HARQ ACK/NAKand retransmission for multi-carrier operation is given in otherappendices.

The above-described embodiments of the present application are intendedto be examples only. Those of skill in the art may effect alterations,modifications and variations to the particular embodiments withoutdeparting from the scope of the application.

1. A method of a subscriber station (SS) comprising: performing networkentry in a multi-carrier wireless environment using a primary carrier;receiving timing information corresponding to the primary carrier;receiving a first control signaling via the primary carrier, the firstcontrol signaling assigning a first secondary carrier; transmittinguplink data via the first secondary carrier using an uplink transmissiontiming of the first secondary carrier, the uplink transmission timing ofthe first secondary carrier being the same as an uplink transmissiontiming of the primary carrier; receiving a second control signaling viathe primary carrier, the second control signaling assigning a secondsecondary carrier without modifying the primary carrier; andtransmitting uplink data via the second secondary carrier using anuplink transmission timing of the second secondary carrier, the uplinktransmission timing of the second secondary carrier being the same as anuplink transmission timing of the primary carrier.